Here is the full list of all 12 Catastronauts achievements.
Completed the first hub
Completed the second hub
Completed the third hub
Completed the fourth hub
Completed the fifth hub
Rescued Sarge from Zastral's grasp
Achieved 3 stars for every level in the first hub
Achieved 3 stars for every level in the second hub
Achieved 3 stars for every level in the third hub
Achieved 3 stars for every level in the fourth hub
Achieved 3 stars for every level in the fifth hub
Achieved 3 stars for every level in the sixth hub